A cryptographic method and system. A plurality of ciphers is identified in a message received by a recipient, such message encrypting a digital asset. A private key associated with the recipient is obtained. The private key corresponds to a public key associated with the recipient. The method includes solving for x in the equation: [(f0(R0−1N′0 mod S)+P′+fλ(Rn−1N′n mod S))/(h0(R0−1N′0 mod S)+Q′+hλ(Rn−1N′n mod S))]*h(x)−f(x)=0 mod p, where (i) P′, Q′, N′0, and N′n correspond to the ciphers in the received message; (ii) R0, Rn and S are data elements of the private key; (iii) f(·) is a polynomial function defined by coefficients f0, f1, . . . fλ that are also data elements of the private key; and (iv) h(·) is a polynomial function defined by coefficients h0, h1, . . . hλ that are also data elements of the private key. The value of x is assigned to the digital asset, which is then stored in non-transitory memory or packaged in a message sent over the data network.